Atlassian – JIRA – J2EE Issue Tracking, Bug Tracking and Project Management Software
“…Tracking and managing the issues and bugs that emerge during a software development project is a critically important task, but one that few development teams do effectively.
JIRA is a J2EE-based, issue tracking and project management application developed to make this process easier for your team…” Usefully, they have a live demo – looks pretty good.